The last decade has seen intense disputes about whether alleged terrorists captured during the nontraditional post-9/11 conflict with al Qaeda and affiliated groups may use habeas corpus to challenge their military detention or military trials. It is time to take a step back from 9/11 and begin to evaluate the enemy combatant legal regime on a broader, more systemic basis, and to understand its application to future conflicts. A leading precedent ripe for reconsideration is Ex parte Quirin, a World War II-era case in which the Supreme Court held that saboteurs admittedly employed by an enemy nation’s military had a right to access civilian courts during wartime to challenge their trial before a military commission. Even though admitted members of an enemy nation’s military had never before accessed the civilian justice system during wartime, the Court in Quirin declined to explain why it reversed course in such a significant fashion. Since and because of Quirin, it has become accepted that literally any individual present in the United States has a constitutional right to habeas corpus.